mpc5121: Move iopin features from board specific to common files.

And in the process eliminate some duplicate register defines.

Signed-off-by: Kenneth Johansson <kenneth@southpole.se>
diff --git a/cpu/mpc512x/Makefile b/cpu/mpc512x/Makefile
index 2be35b2..8ba8ae8 100644
--- a/cpu/mpc512x/Makefile
+++ b/cpu/mpc512x/Makefile
@@ -25,7 +25,7 @@
 LIB	= $(obj)lib$(CPU).a
 
 START	= start.o
-COBJS	= traps.o cpu.o cpu_init.o speed.o interrupts.o serial.o fec.o i2c.o
+COBJS	= traps.o cpu.o cpu_init.o speed.o interrupts.o serial.o fec.o i2c.o iopin.o
 
 SRCS	:= $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS))